Abstract
The objectives of this study were to determine the performance and exhaust emissions of a gasoline engine with a fuel injection system (Subaru EH72 FI) modified for operation with addition of some amount of synthethis gas ("syngas") containing hydrogen in the intake manifold and to compare the results with those obtained for gasoline operation at the same engine load and crankshaft speed. As the engine working load, Endress ESE 1506 DSG-GT ES DUPLEX electric generator with effective output in the range from 3 to 15 kW is used. Syngas was generated by partial oxidation of gasoline with air in a plasma-assisted fuel converter. Steam was added to the gasoline-air converter fuel mixture to reduce the amount of soot produced in a plasma reactor, and thereby increase its reliability and operational life. A completely automated engine and plasma converter test bench was developed. Experimental results clearly demonstrate substantial reduction in the NOx engine emissions when hydrogen-rich synthesis gas generated by a plasma-assisted fuel converter was added to the intake manifold of the tested engine. The most prominent reduction in harmfull pollutions is observed for lean conditions. Meanwhile total gasoline consumption (including gasoline needed for the plasma-assisted converter) with syngas addition increases compared to the original engine. This increase ranges from 1.05 for a stochiometric composition of the fuel mixture to 1.15 times for a lean mixture (excess air coefficient of the fuel mixture lambda = 1.26). As a continuation of this work, investigations of ultralean regimes (lambda similar to 1.43-1.67) are scheduled to validate the theoretical results obtained in (Migun et al., 2006).